Stones used for astrological reasons may have some natural inclusions , but all these stones should be transparent, translucent and flawless.
Wearing Navaratna depends on three factors ,purity of the stone is very important to transmit the vibrations to the wearer . It is believed that gemstones with cracks will block the path of the light or the rays.. These gems should be natural without any treatment. Larger stones are recommended to convey the ,maximum benefit to the wearer . The will power and the belief of the wearer are also important .
According to the Vedic Sanskrit Authority only pure top quality gems are considered to be desirable. Sri Agni Puranam Chap:246 states “A gem free from all impurities and radiating its characteristic internal luster should be looked upon as an escort of good luck . A gem which is cracked and devoid of luster or appearing rough or sandy should not be used at all.
Sri Garuda Purana chapter 70 states that ” if anyone wears a gem with many flaws out of ignorance , then, grief, anxiety, sickness, death, loss of wealth and other evils torment them.”
Physical Properties of the Nine Gems
Corundum
Out of the nine, five stones namely Ruby, Blue Sapphire, Pathmaraga, White Sapphire and Yellow Sapphire belong to the Corundum family.
Crystal system: Trigonal
Refractive index:1.759-1.760
Hardness: 9.0
Chemical composition: Aluminium Oxide
Density 3.98
Name derived from Sanskrit, “Kuruvinda”. Corundum is a crystalline form of Aluminium Oxide .It has different colours when impurities are present. Transparent specimens are used as gems , called Ruby if red, Padmaraga if pinkish orange while all other colours are called sapphires, usually with the colour specified as a prefix to the word sapphire for example Yellow Sapphire.
Pure corundum is colourless often called white sapphire. Chromic oxide causes brilliant red , thereby producing rubies. Ferric oxide causes yellow colouration , titanium oxide produces vivid-blue. Some corundum in Sri Lanka have patchy colours and colour bands . Sri Lankan corundum typically carries zircon crystals as inclusions known as ‘zircon haloes’.
Pearls
Hardness: 2.5-4.5
Chemical composition: calcium carbonate.
Natural Pearls are organic gems formed in bodies of certain salt water and fresh water Mollusks . They are made up of mostly fine platy crystalline layers called Nacre causing the distinctive pearly luster . Appearance is translucent to opaque . Body colour is white or cream, pink green black and blue colours are also available . The cause of colour is due to the interference of light reflected off platy crystal layers in nacre. Identification characteristics are gritty to cutting edges of teeth. Most imitations are smooth. There are cultured pearls. There are also glass and plastic imitations in the market.
The shapes of pearls are categorized as round, pear shaped, egg shaped and drop shaped.
Hessonite Garnet
Crystal System: Cubic
Refractive Index: 1.740
Hardness 7.25
Specific Gravity: 3.5-3.7
Chemical Composition: Calcium Aluminium Silicate.
It is a variety of grosular garnet
The colour of hessonite is like the colour of honey shining under a ray of light. The colour is due to the presence of Manganese. This gem contains inclusions which look like scattered island of flat bubbles . The best hessonite garnets are found in Sri Lanka, as the Spessartite too, occurs in deep goden yellow and yellow brown colours ,these could be mistaken for hessonite.
Tourmaline
Crystal system: Trigonal
R.I : 1.624-1.644
Hardness: 7.5
S.G: 3.5
Chemical Composition: A complex Borosilicate of Aluminium
It exhibits more range of colours than any other mineral . It has colours such as red, blue ,yellow, pink, black and green. Green is from Iron ,Chromium and Vanadium. Pink is from Manganese. Its original- Sinhala name is Thora- malli. Mal is the Sinhalese term for flower . Thora is the name of a plant .Tourmaline is a pyroelectric mineral , meaning when warmed it attracts dust and light weight particles.
Varieties:
Rubellite: Pink to red Tourmaline
Indicolite: Light to dark Tourmaline
Dravite: Brown Tourmaline
Anchorite: Colourless Tourmaline
Schorl: Black Tourmaline
Water melon Tourmaline: Tourmaline with red center surrounded by a green layer.
Verdelite: Name rarely used to describe green tourmaline.
Sybarite: Purple variety.
Paraiba Tourmaline: Neon blue variety
Chrysoberyl Cat’s Eye
Crystal system: Orthorhombic
R.I : 1.746-1.755
Hardness: 8.5
S.G 3.5-3.8
Chemical composition: Berryllium Aluminium Oxide
Ordinary chrysoberyl is a yellowish green , transparent to translucent. In Sri Lanka chrysoberyls are found as water worn pebbles. Cymophane is popularly known as cat’ eye. This variety exhibits a pleasing chatoyant effect that reminds one of an eye of a cat. When cut to produce a cabochon the mineral forms a light green specimen with a silky band of light extending across the surface of the stone . Chatoyancy , like Asterism is a reflection effect brought about by the stone inclusions . Some common colours in which cat’s eye occurs are milky white to grey, bluish or greenish white and apple green and greenish orange.
